Known devices of this kind are not capable of providing sufficient mixing and burial of crop-residue. This means that the crop-residue is incompletely covered giving less than ideal conditions for the subsequent drilling operation and not providing sufficient weed control.
The effectiveness of these so-called minimum tillage cultivators can be improved by first baling the crop-residue or burning it but baling is not always justifiable commercially and burning is becoming increasingly unacceptable for environmental reasons.